Fetal heart rate deceleration is the most simple and effective method which provides reference and analysis for judging whether a fetus is safe during the delivery period. During the whole delivery course, about 50% to 70% of delivery cases have fetal heart rate deceleration. Their representative cases are early deceleration, late deceleration and variable deceleration. Early deceleration is generally caused because the fetal head is compressed, which has little relation with fetal hypoxia. However, if the early deceleration occurs during the early phase of the delivery course, the umbilical cord is compressed and the fetus may have hypoxia. Late deceleration is generally caused because the lack of oxygen causes the vagus nerve to have hyperactivity and/or myocardium is inhibited, which is generally regarded as reference. It mainly occurs during the uterus-placental blood flow reduction and fetal hypoxia caused by placental dysfunction. Variable deceleration is mainly caused because the umbilical cord is compressed. When severe variable deceleration or atypical variable deceleration occurs, they prompt that the fetus is distressed.
Currently, there are no uniform quantitative criteria for clinically judging fetal heart rate deceleration and the type thereof. Therefore, the method for clinically and automatically identifying the fetal heart rate deceleration data are calculated mainly according to the deceleration standard set by the duration, decrease amplitude and other experiential parameters. That is, a fetal monitoring module firstly collects the fetal heart rate, identifies the fetal heart rate baseline, and then calculates the number of decelerations and the duration, amplitude, types and so on under the baseline, according to the standard set by clinical deceleration experiential parameters. However, such method for identifying deceleration with the experiential parameters in the clinical application has the following disadvantages: firstly, as there are various deceleration types in the clinical environment; the experiential parameters are not necessarily accurate and may not cover all cases, thus facilitating the deceleration identification data to have large errors; Secondly, the method may not identify continuous deceleration and not eliminate the baseline variation part, thus resulting in the number of identified deceleration data being lower than the actual number and resulting in counting the baseline variation part into the deceleration; thirdly, there may be the mixing of many deceleration types during the delivery; The method may only identify one type of one deceleration datum and may not identify the composite deceleration data.
The experiential parameters may not meet the requirements of automatic deceleration identification. The objective of the invention is to overcome the following disadvantages: the deceleration errors identified according to the fetal heart rate deceleration automatic identification method in the prior art are large; continuous deceleration may not be identified; the baseline variation may not be eliminated; and composite deceleration may not be identified. The invention, with a dynamic threshold area algorithm, a continuous peak inspection algorithm and a composite deceleration inspection algorithm, may effectively eliminate the baseline variation part and accurately identify each deceleration and the type thereof.